One type of a measuring instrument for detecting a liquid level in boilers and water storage tanks is a float liquid level meter.
One example of this float liquid level meter is a magnet-installed float liquid level meter, capable of securely detecting at all times a surface of a liquid inside a container to be detected, by using a magnet-installed float of a small size and of light weight (for example, see Patent Document 1).
The invention described in Patent Document 1 relates to a magnet float liquid level meter. More specifically, the invention described in Patent Document 1 has a tubular body provided in a protruding manner from an inner surface of a standing column opposing an opening of a lower connecting pipe among upper and lower connecting pipes that connect a liquid container of which a liquid level is to be detected and the standing column, which tubular body configures a magnetic powder reservoir, and by disposing a magnet detachably with a screw within the tubular body, the magnetic powder inside the liquid is attracted to the magnet and is grown inside the magnetic powder reservoir, and any liquid flow obstruction caused by growth in magnetic powder easily generated within the connecting pipes and on the inner surface of the standing columns is eliminated, thus simplifying cleaning of grown magnetic powder.
FIG. 1 is a schematic view of a float liquid level meter 10. A standing column 11 serving as a tubular member is connected via connecting pipes 12 and 13, to a boiler not shown that serves as a liquid container. Inside the standing column 11 disposed vertically in a longitudinal direction, a float incorporating a permanent magnet is inserted in a movable manner. The float is integrated with the permanent magnet whose magnetization direction is in a direction orthogonal to the longitudinal direction of the standing column 11.
On the outer surface of the standing column 11, a float liquid level indicator 14 is fixed along the longitudinal direction of the standing column 11, by using a fixing metal fixture 15. Moreover, a valve handle 16 is for discharging contents inside the standing column 11 when cleaning.
FIG. 2A is an appearance perspective view showing a conventional example of an indicator for the float liquid level meter shown in FIG. 1, FIG. 2B is a side view of a rotatable slat used in the indicator shown in FIG. 2A, and FIG. 2C is a front view of FIG. 2B.
In the indicator 14 shown in FIG. 2A, a plurality (in the drawing there are 13 pieces, however it is not limited to this) of rotatable slats 20 are disposed within a housing 21 in a longitudinal direction, being parallel to each other and in a rotatable manner.
The rotatable slats 20 shown in FIGS. 2B and 2C can have a rotation shaft 25 described later penetrate therethrough, and is a component adhering two pieces of members 20-1a, 20-2a capable of housing a tubular permanent magnet 20d. The member 20-1a is formed of semi-cylindrical portions 20-1b, 20-2b, and a claw portion 20-1f shown by broken lines on both ends of a surface of a part serving as wings formed by press-working. The member 20-2a also has a similar shape as the member 20-1a. The members 20-1a and 20-2a are colored in two colors, however at least one can be color free. The two pieces of members 20-1a and 20-2a are adhered together in a state of housing the permanent magnet 20d between the center semi-cylindrical portions 20-1b and 20-2b. The permanent magnet 20d is magnetized in a radial direction, and is disposed to have either side of the semi-cylindrical portions 20-1b and 20-2b (parts serving as wings) serve as the N-pole and S-pole, respectively. The rotatable slat 20 is formed by bending the claw portions 20-1f towards their respective counter sides.
FIG. 3 is an appearance perspective view showing a state taking off a lid 22 (23) of the indicator 14 shown in FIG. 2A, which lid 22 (23) is made of non-magnetic material, and having supporting metal fixtures 24, 24 pulled out from the housing 21 being made of non-magnetic material. FIG. 4 is an appearance perspective view showing a state in which the rotation shaft 25 is pulled out from the supporting metal fixtures 24, 24 shown in FIG. 3. FIG. 5 is an appearance perspective view showing a state in which the rotation shaft 25 is inserted into through holes 26, 26 of the pair of the supporting metal fixtures 24, 24 shown in FIG. 3.
The supporting metal fixtures 24, 24 are a pair of elongated members made of non-magnetic material, and are formed having the through holes 26 of the number of rotatable slats 20 facing each other at regular intervals.
The rotatable slat 20 is disposed between one pair of the supporting metal fixtures 24, 24, and the rotation shaft 25 is inserted through the through hole 26, the rotatable slat 20, and the through hole 26.